Yarn winding mechanism

ABSTRACT

A yarn winding mechanism for removing the treated yarn from yarn treating apparatus such as stuffer crimpers and the like. The treated yarn is wound upon a spool into a yarn winding by means of a rotating driving roll engaging the peripheral surface of the winding. The winding is normally in engagement with the driving roll but is movable out of engagement to halt the winding operation. The yarn winding is mounted upon pivoted lever means, and movement to the disengaged position is accomplished by means of a cable attached at one end to the pivoted lever means and at the other end to a rotatable drum. A drum drive means operated by a fluid pressure motor selectively engagable with the drum to rotate the drum through a predetermined arc, thus pulling the cable and disengaging the winding from the driving roll. The motor operates in response to means sensing the quantity of yarn in the exit portion of the treating chamber. A means for sensing a break in the yarn is also provided, which can disengage the winding from the driving roll and can stop the feeding of yarn into the yarn treating chamber.

United States Patent 1 Trifunovic et al.

[73] Assignee: Joseph Bancroft & Sons C0.,

Wilmington, Del.

[22] Filed: May 6, 1974 [21] Appl. No.: 467,153

Related US. Application Data [60] Division of Ser. No. 338,048, March 5, 1973, Pat. No. 3,837,053, which is a continuation-in-part of Ser. No. 225,553, Feb. 1, 1972, abandoned.

[52] 11.8. Cl. 242/18 DD; 242/36; 242/45 [51] Int. Cl B65h 54/02; B65h 63/00 [58] Field of Search..... 242/18 DD, 18 R, 36, 37 R,

[56] References Cited UNITED STATES PATENTS 2,740,992 4/1956 Shattuck 28/].7 3,300,830 1/1967 Johnson, Jr..... 28/l.7

3,579,760 5/1971 Cancer 61: a1. 28/].7 3,605.222 9/1971 Cabello 28/l.7 3,675,286 7/1972 Cabello 28/].7 3,743,202 7/1973 Hoffsommer et a1. 242/45 [4 Sept. 16, 1975 Primary Examiner-Stanley N. Gilreath 57 ABSTRACT A yarn winding mechanism for removing the treated yarn from yarn treating apparatus such as stuffer crimpers and the like. The treated yarn is wound upon a spool into a yarn winding by means of a rotating driving roll engaging the peripheral surface of the winding. The winding is normally in engagement with the driving roll but is movable out of engagement to halt the winding operation. The yarn winding is mounted upon pivoted lever means, and movement to the disengaged position is accomplished by means of a cable attached at one end to the pivoted lever means and at the other end to a rotatable drum. A drum drive means operated by a fluid pressure motor selectively engagable with the drum to rotate the drum through a predetermined are, thus pulling the cable and disengaging the winding from the driving roll. The motor operates in response to means sensing the quantity of yarn in the exit portion of the treating chamber. A means for sensing a break in the yarn is also provided, which can disengage the winding from the driving roll and can stop the feeding of yarn into the yarn treating chamber.

23 Claims, 13 Drawing Figures F'SOSSSO PATENTEU SEP 1 6 I975 SHEET 2 0F 6 PATENTEB SEP 1 6 I975 3 905 56 0 sum u U? 6 FIGID YARN WINDING MECHANISM This is a division of application Ser. No. 338,048 filed Mar. 5, I973, now US. Pat. No. 3,837,053, which is a BACKGROUND OF THE INVENTION This invention relates generally to a mechanism for removing treated yarn from the yarn treating chamber of a yarn treating apparatus such as stuffer crimpers and the like.

In yarn treatment apparatus such as stuffer crimpers, yarn is fed into a yarn treating chamber for operations such as crimping, and is then removed from the chamber and wound on a spool into a yarn winding from which it is passed to further treatments or operations. Yarn is fed into the yarn treatment chamber at a predetermined rate and is removed therefrom at a predetermined rate. It would thus seem that the yarn removal mechanism would then simply operate at a constant rate. However, this is not the case, for fluctuations in the yarn feeding or treatment process necessitate the use of a controllable removal or winding mechanism The prior art shows several basic types of controllable or compensating yarn winding mechanisms. Included are biasing mechanisms that engage the yarn to remove any slack beyond a predetermined amount present in the treated yarn between the treating chamber and the winding, and, of course, mechanisms for varying the speed of the yarn winding drive means in response to a sensing unit in the treating chamber. Slack control mechanisms have been found to be unacceptable because they fail to provide the necessary degree of control. Likewise, devices which vary the speed of the yarn winding drive means have proved to be complicated and unreliable.

A third control method has therefore been adopted, consisting of a yarn winding driven in rotation by a driving roll engaging the peripheral surface of the winding. Control of the speed of winding is accomplished by varying the spacing between the winding spool and the driving roll from full engagement through partial engagement to full disengagement in response to a sensing mechanism sensing the quantity of yarn in the exit portion of the treating chamber. At full engagement the winding rotates at maximum speed. At the various portions of partial engagement, slipping occurs between the winding and the driving roll, with accompanying reduction in winding speed. At full disengagement, the winding operation is halted. In actual operation, the winding is constantly engaging and disengaging the driving roll, several times per minute, for example. The prior art offers a number of mechanisms for moving the winding into and out of engagement with the driving roll, such as that shown in US. Pat. No. 2,740,992 issued Apr. 10, 1956. These prior art mechanisms have proved to be unreliable for several reasons, including their general complexity and their inconsistency in compensating for the constantly increasing diameter of the yarn winding.

With their systems of interacting levers and'arms, the prior art mechanisms have proved to be difficult to package and their placement with regard to the treating apparatus is quite limited. These factors pose problems in the design of new treating equipment and the installation of this type of a winding mechanism on existin treating equipment.

It 'is necessary to separate the yarn winding and the driving roll positively and precisely each time the sensing mechanism soindicates, so that the response is timely and the predicted or desired degree of slippage willtake place between the yarn winding and the driving roll. It is also necessary to separate the yarn winding and the driving roll each time by the same predetermined distance, so that the time of each cycle remains substantially contant, and so as not to lift the yarn out of the yarn traverse mechanism associated with the yarn winding or to otherwise disturb its operation. The prior art devices have generally proved to be so inconsistant in operation as not to satisfy these requirements.

SUMMARY OF THE INVENTION This invention is directed to a yarn winding mechanism, of the type commonly known as a package drum type, which overcomes the disadvantages of the sys tems known in the prior art. Specifically, it is precisely controllable and operates continuously in a predictable manner.

The yarn winding is developed upon a winding spool that is driven in rotation by a driving roll engageable with the peripheralsurface of the winding. Either the winding spool or the driving roll-is mounted on a support that allows lateral movement with respect to the other between positions of full engagement and complete disengagement.

The normal position'for the winding is in full engagement with the driving roll, and this can be accomplished by suitable biasing or by placement of the movable element in a plane above the fixed element, utiliz ing the force of gravity to accomplish the biasing action. I

Movement to the disengaged position is accomplished by means of a cable attached at one end to the support element and at the other end to a drum (or a portion ofa drum) at a point spaced from the drum axis so that rotation of the drum pulls the cable. The drum is rotated through a predetermined are by a motor operated by a sensing mechanism in the yarn treating chamber.

The drum is biased in rotation to the extent necessary to preclude the development of slack in the cable, as the winding increases in diameter as more yarn is wound thereon, and the movably mounted element moves to accommodate the increased diameter.

A yarn break sensing system forms a part of this inventive concept, and includes a lever that pivots in response to a break in the yarn to operate the mechanism to cause the driving roll and the yarn winding to separate, thus halting the winding operation, and/or causing the mechanism feeding yarn into the chamber to come to a halt.

The yarn winding mechanism utilizing the inventive teachings set forth above provides reliable service and is easily designed into new machinery or added to existing machinery.

BRIEF DESCRIPTION OF TI -IE DRAWINGS FIG. 1 is a side elevational view of a stuffer crimper apparatus utilizing the yarn winding mechanism of the invention;

FIG. 2 is a side elevational view ofa first embodiment o the cable operating mechanism of the invention;

FIG. 3 is a side view of the cable winding drum of FIG. 2;

FIG. 4 is an end view of the biasing mechanism of cable winding drum of FIG. 2;

FIG. 5 is a side elevational view of the yarn break sensing mechanism of the invention;

FIG. 6 is a side elevational view of a second embodiment of the cable winding mechanism of the invention;

FIG. 7 is a side view of the cable winding drum of FIG. 6;

FIG. 8 is an end view, partially cut away, of a third embodiment of the cable winding mechanism of the invention;

FIG. 9 is an end view, partially cut away, of a fourth embodiment of the cable winding mechanism of the invention;

FIG. 10 is a side elevational view of a fifth embodiment of the cable winding mechanism of the invention;

FIG. 11 is a side elevational view of a sixth embodiment of the cable winding mechanism of the invention;

FIG. 12 is an end view of the sixth embodiment of the invention taken through line 1212 of FIG. 11; and

FIG. 13 is a side elevational view of the sixth embodiment of the invention taken through line 1313 of FIG. 12.

DESCRIPTION OF THE PREFERRED EMBODIMENTS This invention is directed to a yarn winding mechanism that can be utilized with many types of yarn treatment apparatus, but which is particularly well suited for use with stuffer crimping apparatus. For this reason this invention is described herein in combination with a stuffer crimper, but it should be understood that its application is not limited to this particular type of equipment.

A stuffer crimper apparatus of known type is shown generally in FIG. 1, and comprises a crimping chamber 10 having an entry portion 11 and an exit portion 12.

Chamber 10 is partially surrounded by a housing 13 containing heating and/or cooling equipment which is commonly used in combination with the crimping process. In the conventional manner, untreated yarn 15 is unwound from a supply package 16 and passes upwardly through a guide tube 17 into the bite of a pair of feed rollers 18 and 19 which feed the yarn into the crimping chamber where it is crimped against a mass of previously crimped yarn in the known manner. Feed roll 19 is biased toward feed roll 18 by a weight 20, which acts through a cable 21 and a pivotally mounted frame 22 upon which feed roll 19 is mounted. The yarn 15 is crimped in the crimping chamber entry portion 11 and then passes upwardly through crimping chamber 10, thereby being exposed to heating and cooling treatments. Back pressure in crimping chamber 10 is controlled by a choke means 21 which projects into the crimping chamber and applied a predetermined pressure to the core of the now crimped yarn 22. A weight 23 operates choke 21. After passing choke 21 the crimped yarn 22 proceeds to crimping chamber exit portion 12 from which it will be removed from the crimping apparatus and wound into a yarn winding for further treatment or textile operations such as weaving.

Normally, feed rolls 18 and 19 are driven at a constant rate of speed, and therefore yarn 15 is fed into the crimping chamber at a constant rate. Theoretically. the crimped yarn 22 should emerge at a constant rate in a fixed proportion to the entry rate of uncrimped yarn 15. However, as a practical matter, the feed rate and the conditions within crimping chamber 10 vary, resulting in the necessity to extract the crimped yarn from exit portion 12 at constantly varying rates in controllable manner. Control of the removal of the yarn from exit portion 12 is based upon maintaining a predetermined quantity of yarn in exit portion 12. In order to sense the level of yarn in exit portion 12, a sensing means 25 is provided and contacts the top of the core of crimped yarn 22. Sensing arm 26 actuates a sensing switch 27 which operates the yarn winding mechanism in a manner to be explained below. Sensing means 25 can be set up to operate the working mechanism in response to a condition above or below a predetermined level of yarn. This sensing means 25 is but one of a number of mechanical and electrical types that can be used to perform this function.

After leaving the exit portion 12 of the crimping chamber the yarn passes over a guide and then through a yarn break sensing mechanism 28 comprising a pair of fixed yarn guides 29 under which crimped yarn 22 passes, and an opposed movable yarn guide 29a over which the crimped yarn 22 passes. Movable yarn guide 29a is carried by a pivotally mounted arm 33 that is biased in the clockwise direction, this bias being resisted by the yarn 22 interacting under tension with guides 29 and 29a. Therefore, ifa break occurs in the yarn, or excessive slack develops in the yarn, yarn guide 29a will be released, allowing arm 33 to rotate clockwise. Arm 33 operates several mechanisms, as explained below, to halt both the winding and the feeding operations. Other types of break sensing mechanisms, such as electrical scanners, can also be used.

The yarn passes from the yarn break sensing mechanism 28 through a traverse means 30 to a yarn winding 31 which is formed upon a winding spool 32 rotatably mounted upon an arm 34. The traverse means 30 insures that the yarn 22 is evenly wound onto winding 31. Arm 34 is in two portions, attached together by an adjustable means such as a bolted connection 34a, so that the angular position of one portion with respect to the other portion can be adjusted. Arm 34 is attached to an operating lever 35 that is pivotally mounted on a shaft 36. Thus spool 32 and winding 31 are laterally movable. Yarn winding 31 is driven in rotation by frictional engagement with a driving roll 38 driven at a constant rate by an electric motor (not shown). The rate of driving roll 38 is selected so that the maximum yarn withdrawal condition can be met. Driving roll 38 acts against a portion or all of the length of the peripheral surface of winding 31, or it can act on a portion of spool 32. Winding 31 is positioned above drive roll 38, and the weight of winding 31 urges it into engagement with driving roll 38. However, other relationships between these two elements can be established, with engagement accomplished by spring biasing means, for

example.

As can be clearly seen from FIG. 1, if lever 35 is pivoted in a clockwise direction, spool 32 will move laterally upwardly and winding 31 will be raised from its position of engagement with driving roll 38; thus the winding'of crimped yarn 22 onto winding 31 will be halted; If desired, intermediate positions of partial engagement can be established and the slippage between winding 31 and driving roll 38 will reduce to the desired level the rate of rotation of winding 31. While winding 31 is shown as the movable element and driving roll 38 is stationary, these roles can be reversed.

Attached to the lower end of arm is a cable 40 that passes around a cable pulley 41 and is then attached to a rotatable cable winding drum 42 at' a point spaced from its axis of rotation. Thus, when drum 42 isro tated through an arc in a counterclockwise direction, cable 40 is pulled, causing clockwise rotation of lever 35 and subsequent lifting of winding 31 from engagement with driving roll 38.

While a cable 40 has been shown, it should be understood that other flexible devices such as belts, tapes, or chains can alternatively be used. One of the key advantages in this invention involves the use of a flexible cable or the like, for this enables the unit that operates the winding 31 to be placed at a point spaced from the' winding itself, the flexible cable being threaded through pulleys or conduits. Such a system eliminates the need for a number of interconnected levers. It is thus much more easily serviced and adjusted than the prior art devices.

In a first embodiment of the invention rotation of drum 42 is accomplished by means of a lever mechanism having a friction shoe that engages the outer periphery of drum 42. A first lever 45 is pivotally mounted at one end on the axle 46 of drum 42 and extends radially beyond the periphery of drum 42 at the other end. Attached to first lever 45 at a pivotal connection 47 is a second lever 48. A friction shoe 49 is mounted on lever 48 offset from the longitudinal axis. Levers 4S and 48 are operated by an expansible chamber motor 50. A piston rod 51 has a yoke 52 connected to lever 48 by a pin connection 53. The flow of pressure fluid to motor is controlled by a solenoid valve 55 that is actuated by the yarn height sensing mechanism 25 through wires 56. Motor 50 is attached to a bracket 57 that is pivotally mounted by means of a bushing 58 on a shaft 59. Other types of motors can also be used within the scope of the invention.

The details of the first embodiment of the drum rotating mechanism of the invention are shown in FIGS. 2, 3 and 4. Drum 42 is rotatably mounted on an axle 46 affixed to and extending through a housing plate 60. (FIG. 4) Cable 40 is received in an annular groove 61 in drum 42 and is attached to drum 42 by means of a screw 62. In order to provide for an adjustment of cable 40, a plurality of threaded holes 63 for receiving screw 61 is provided on drum 42. Drum 42 is biased in the counterclockwise direction with just enough force to keep slack from forming in cable 40, but with insufficient force to lift winding 31 from its engagement with drive roll 38. The biasingforcc is provided by a coil spring 64 on the opposite side of housing plate from drum 42 and engaging a collar 66 fixed on axle 46. Plate 60 is provided with an arcuate slotted opening 68.

Through this opening 68 extends a pin 69 which is mounted on one face of drum 42. An arcuate end portion 70 of spring 64 engages pin 69. Arcuate slotted opening 68 limits the extent of rotational movement of drum 42 and therefore slot 68 is of sufficient lengthto allow winding 31 to develop a suitablediameter. Pin 69 can be received in anopening 71 and a plurality of such openings 71 are provided on drum 42 to allow compensation for different lengths of cable 40. Dr um'42 also has an annular friction surface '74 upon which friction shoe 49 acts. A pair of adjustable stopscrews 72 and 73 limit the movement of lever 45 to control the length of the are through which drum 42 is rotated as explained below.

The first embodiment of the invention operates in the following manner: Yarn winding 31 is driven in rotation by driving roll 38and the crimped yarn 22 exiting from exit portion 12 is wound onto winding 31. So long as the quantity of yarn in exit portion 12 remains substantially at a predetermined level, winding 31 remains in' engagement with driving roll 38. If, however, the quantity of crimped yarn in exit portion 12 drips below the predetermined level, such is sensed by sensing arm 26, which operates motor 50 through switch 27 and motor valve 55. Piston rod 51 then moves upwardly, pivoting arm 48 about pivot joint 47. This pivotal movement of arm 48 initially causes friction shoe 49 to engage friction surface 74 of drum 42, thus locking drum 42 and arm 48 together. Further counterclockwise movement of arm 48 causes arms 45 and 48 to pivot together on shaft 46. Since arm 48 is locked to drum 42, drum 42 then is rotated counterclockwise on shaft 46, pulling on cable 40. Lever 35 is thus caused to pivot about shaft 36, moving arm 34 and winding 31 upwardly. The length of the arc of rotation of drum 42 and, ultimately, the amount of upwardly movement of winding 31, is limited by the amount of movement of lever 45, as set by stops 72 and 73. If winding 31 is to be completely disengaged from driving roll 38, stop 72 is appropriately positioned. Lower settings of stop 72 will cause only partial disengagement of winding 31, thus slowing but not halting, the winding operation.

Another key feature of this invention resides in the fact that the mechanism continuously compensates for the increasing diameter of winding 31, and the are of rotation transcribed by drum 42 is the same no matter what the diameter of winding 31, so that the precise desired degree of disengagement is achieved each time motor 50 operates. The counterclockwise biasing of drum 42 by spring 64 allows no slack to develop in cable 40 and drum 42 rotates counterclockwise as the diameter of winding 31 grows. Thus, the point on friction surface 74 engaged by shoe 49 is different for each operation of motor 50, but the effect on winding 31 is the same.

When pressure to motor 50 is released, arms 45 and 48 are free to pivot clockwise to their normal position under the action of their own weight, or by bias means. Disengagement of shoe 49 from surface 74 is assured by the interposition of tension spring 75 between arm 45 and an offset position 76 of arm 48. Clockwise rotation of arm 48 is limited by offset portion 76 lightly engaging surface 74, or a separate limiting stop can be provided.

The embodiment shown in FIG. 10 also utilizes a drum42 having a groove 61 receiving cable 40. Friction surface 74, annularly arranged on drum 42, can be knurled or roughened, if desired. Drum 42 is biased to remove slack from cable 40, in the manner described above.

Pivotally mounted on axle 46 is a first arm having an end portion 161 and a perpendicular portion 162. Pivotally connected to end portion 161 by a pin 164 is a second arm 165. Yoke 52, operated by the motor 50, is connected to the other end of arm 165 by means of a pin 53. Second arm 165 has a cam portion 167 offset from the longitudinal and pivot axes.

Pivotally connected by means of a pin 168 to perpendicular portion 162 of arm 160 is a third arm 170. Friction shoe 171 is carried by arm 170, at a point adjacent to friction surface 74. Friction shoe 171 can also be knurled. Arm 170 is interposed between cam portion 167 and friction surface 74. A spring 173 is attached to 3 other than the pivoted arm, such as in a slot in arm 160;;5 In operation, arm 165 is pivoted by the motor. This;

initially causes cam portion 167 to engage arm 170 to move friction shoe 171 into engagement with friction surface 74. Continued pivoting of arm 165 causes arm 165 and arm 160 to pivot together about axle 46. Since the arm 160 and 165 are locked to drum 42 by the action of friction shoe 171, drum 42 is rotated.

Shown in FIG. 5 is a mechanism for reacting to a break in the yarn to stop the yarn winding operation and, if desired, to stop the feed rolls 18 and 19 from feeding yarn into the crimping chamber. As discussed above in regard to FIG. 1, the invention includes a mechanism 28 for sensing a break in the yarn. The result of the occurrence of a break or of an undesired degree of slack in the yarn is the clockwise rotation of element 33. It is the clockwise rotation of element 33 that operates the mechanism shown in FIG. 5.

The yarn break mechanism comprises a beam 80 pivotally attached at one end to lever 35 by a pin 81. Cable 40 can also be attached to lever 35 by means of pin 81. Beam 80 has a plurality of teeth 82 on its underside. Each tooth 82 has a side 82a slanting inwardly away from pin 81 and a side 82b substantially perpendicular to the axis of beam 80. Beam 80 is supported by a pivotally mounted arm 84, which as at its lower end a pawl 85 loosely secured by a nut and bolt assembly 86. Pawl 85 engages teeth 82. Fixedly attached to the other end of arm 84 is a lever 87 which is interconnected with arm 33 (through means not shown) and which reacts to clockwise movement of arm 33, causing arm 84 to pivot in the clockwise direction. When arm 84 is rotated in response to a break in the yarn, pawl 85 acts on the side 82b of the tooth 82 which is engaged, and thus pulls beam 80 to the left, as shown, rotating lever 35 clockwise and lifting yarn winding 31 from engagement with driving roll 38, thus halting the winding operation. By suitable mechanical or electrical connections (not shown) this mechanism can also disengage or deactivate the drive to feed rollers 18 and 19, thus halting the yarn feed operation. As lever 35 moves clockwise in response to the increasing diameter of winding 31, teeth 82 are pushed over pawl 85, maintaining the engagement therebetween. Compensation is also made for the constant cyclic movement of lever 35 in response to the pulling and relaxing of cable 40. By mounting pawl 85 loosely on bolt 86 it can move a predetermined distance with beam 80 without disturbing arm 84. Pawl 85 is in the solid line positon when cable 40 is relaxed. When cable 40 is pulled beam 80 moves to the left an incremental amount equal to or less than the distance pawl 85 is free to move, and pawl 85 moves to the position shown in phantom. When cable 40 is again relaxed, beam 80 moves back to the right, carrying pawl 85 along. When pawl 85 reaches the limit of its leftward movement (shown in phantom) further movement of beam 80 simply causes the next tooth to jump over the tip of pawl 85, by virtue of inclined side 82a. I

Another embodiment of the drum operating means is shown in FIGS. 6 and 7. As in the first embodiment, the cable 40 is received in a groove 61 of drum 42. In this embodiment, however, the friction surface portion of the drum 42 is not flat, as in the first embodiment, but comprises a generally V-shaped annular channel 90. A first arm 94 is pivotally mounted at one end about drum axle 46, and extends radially outwardly therefrom. At the other end of first arm 94 is a pivotal connection 95 to which a second arm 96 is attached. Arm 96 has a V- shaped friction shoe 97 of design complementary to channel 90. Friction shoe 97 is offset from the axis of arm 96 so that counterclockwise rotation of arm '96 about pivotal connection 95 will cause shoe 97 to engage channel 90. Piston rod 51, actuated by a motor (not shown in FIGS. 6 and 7) is attached toarm 96 by screw means 98. Arm 94 has a flanged portion 99 that extends over arm 96, and a compression spring 100 is interposed between flange 99 and the upper surface of arm 96 to bias shoe 97 away from channel 90. As in the first embodiment a pair of opposed screw stops 72 and 73 are engagable with arm 94 to limit the length of arcuate movement of arms 94 and 96 and thus drum 42. Clockwise movement of arm 96 is limited by its positive engagement with piston rod 51.

The operation of this embodiment is quite similar to that of the first embodiment. Upon operation of piston rod 51, arm 96 is pivoted about pivot connection 95 until friction shoe 97 engages groove 90, whereupon arm 96 and drum 42 are locked together. Continued movement of piston rod 51 then causes rotation of both arms 94 and 96 about axle 46. Since arm 96 and drum 42 are locked together, drum 42 rotates, pulling cable 40 and disengaging winding 31 from driving roll 38. When the motor is deactivated, arms 94 and 96 return to the position shown, releasing drum 42 to allow reengagement of winding 31 and driving roll 38.

Another embodiment of the invention is shown in FIG. 8. In this embodiment the friction shoe and motor are positioned on the inside of the drum. This offers the advantages of a more compact design and a lesser number of parts. Cable is attached at one end to lever 35 in the manner explained above, and at the other end to the periphery of a hollow cylindrical drum 121. The cable 120 is attached to drum 121 by a screw 123. Drum 121 is rotatably mounted on an axle 124 attached to the machine frame 125. One of the ends 122 of drum 121 is closed, and the drum is supported on axle 124 by a bushing 127 in end wall 122. Drum 121 has an inner friction surface 126 that can be knurled or otherwise treated to improve its frictional properties. An expansible chamber motor 130 having a fixed stroke length is pivotally mounted to frame by means ofa pivotal mount 131 that extends inside drum 121. Motor has a piston rod 132 carrying a friction shoe 133. Pivot mount 131 is adjacent inside frictional surface 126 and motor 130 extends across the inside of drum 121. An adjustable stop 135 mounted on frame 125 engages motor 130 to limit its counterclockwise pivotal movement. When motor 130 rests against stop 135, friction shoe 133 is at least slightly spaced from frictional surface 126. A coil spring 136 has one end 137 attached to axle 124, while the other end 138 is attached to the side of drum 121. Spring 136 biases drum 121 in the clockwise direction. as shown.

The embodiment shown in FIG. 8 operates in the following manner: A signal from sensing means 25 energizes motor 130, causing pistor rod 13?. to drive fric tion shoe 133 outwardly. The first portion of the stroke of motor 130 moves shoe 133 into contact with surface 126, thus locking shoe 133 and drum 121 together. The further stroke of motor 130 causes shoe 133 to push against surface 126 with a force having a component tangential to surface 126. Drum 121 is thus caused to rotate in the clockwise direction. Motor 130 pivots during the stroke. Finally, the position shown in phantom is achieved, at the limit of the outward stroke of motor 130. Motor 130 pivots during the stroke. Finally, the position shown in phantom is achieved, at the limit of the outward stroke of motor 130. Motor 130 is of the double-acting type or the biased-return type, so that when deactivated it will return to the position shown in solid lines, thus releasing drum 121. The effective length of the stroke of motor 130 upon drum 121 is controlled by stop 135. To shorten the effective stroke, stop 135 is so manipulated as to move the initial position of motor 130 upwardly. Thereby, shoe 133 will ini tially be a greater distance from surface 126 and a greater portion of the stroke of motor 130 will be utilized in moving shoe 133 into engagement with surface 126. Thus, a lesser amount of the stroke will be available to rotate drum 121, and its are of rotation will be less. Spring 136 operates to remove slack from cable 120 in the same manner as explained above with regard to the other embodiments.

Still another embodiment of the invention is shown in FIG. 9. Cable 120 from lever 35 is wrapped around a portion of the outer surface of a drum 121 and is fastened thereto by screw means 123, as in the preceding embodiment. Drum 121 is again rotatably mounted on an axle 124, which is supported by a frame 125, by means of a bushing 127 in end wall 122. Drum 121 has an inner frictional surface 126 that can be knurled or otherwise treated to enhance its frictional pro erties. A coil spring 136 having one end 137 attached to axle 124 and the other end 138 attached to end wall 122, is arranged to bias drum 121 in the clockwise direction to eliminate slack in cable 120.

As was the case in the embodiment of FIG. 8, an expansible chamber motor 130 having a fixed stroke length is pivotally attached to frame 125 by a pivot connection 131, located adjacent surface 126 so that motor 130 extends across the inside of drum 121. Pivot connection 131 spaces motor 130 sufficiently from frame 125 so that motor 130 is inside drum 121. Motor 130 operates a piston rod 132.

A pin 140 is also mounted on frame 125 and an arm 141 is movably mounted thereon by means of an elongated slot 142 substantially parallel to the axis of arm 141. Thereby, arm 141 can move pivotally and axially. Rotatably attached to the other end of arm 141 by means of a shaft 144 is a disc (or portion of a disc) 145. Piston rod 132 is pivotally attached to disc 145 by means of a shaft 146. The peripheral surface of disc 145 can be knurled or otherwise treated to enhance its frictional properties. Disc 145 also has an elongated arcuate slot 147, in which is movably mounted a limiting stop 149. A pair of locking screws 150 hold stop 149 fixed in position in slot 147. Stop 149 extends upwardly from the side surface of disc 145 to such an extent as to engage the side 151 of arm 14] when disc 145 is rotated. A tension spring 153 is attached between arm 141 and a pin 154 on frame to bias arm 141 to the position shown in FIG. 9.

When motor is actuated by a signal from the yarn sensing means 25, piston rod 132 is driven outwardly. The initial outward movement of piston rod 132 causes disc to rotate clockwise, until stop 149 engages the side 151 of arm 141. At this point in the cycle of operation, disc 145 has not contacted surface 126 of drum 121. Further stroke of piston rod 132 causes disc 145 to move into engagement with surface 126, with arm 141 pivoting clockwise. The stroke of piston rod 132 continues, now imparting a force against surface 126 which has a component tangential to surface 126, motivating the drum to clockwise rotation. The slotted connection 142 allows arm 141 to move longitudinally to allow rotation of drum 121. When motor 130 is deactivated, the components return to their original position, freeing drum 121.

The maximum of the rotational movement that can be imparted to drum 121 is limited by the length of slot 142. However, lesser amounts can be provided by the use of stop 149. The closer stop 149 is to arm 141 at its initial position, the longer the arc imparted to drum 121, because less of the stroke of piston rod 132 is utilized to rotate disc 145 prior to driving disc 145 into contact with surface 126. A stop 149 is adjusted away from arm 141, less of the stroke of piston rod 132 is ultimately available for the drum rotating part of the operating cycle and, due to the fixed length of the stroke, arm 141 will not be driven upwardly to the full extent of slot 142. Thus, the rotation imparted to drum 121 with each stroke of motor 130 can be adjusted.

In still a further embodiment of the invention, shown in FIGS. 11-13, the drum is operated by a spring clutch mechanism. A frame member 200 is journaled to support a rotatable shaft 202, which is held in place by a pair of collars 203 and 204. A spring clutch generally indicated at 205 is supported by shaft 202. Clutch 205 consists of four basic parts: A first clutch element 208 is locked to shaft 202 by a lockscrew 210. First clutch element 208 has an annular clutch surface 211 and a stem portion 212 extending along shaft 202. A second clutch element 214 is rotatably mounted upon stem portion 212, being held in place by a lock ring 215. Second clutch element 214 also has a clutch surface 216 adjacent to the clutch surface 211. A spring 218 is wound around clutch surfaces 211 and 216. One end 219 of spring 218 is anchored to first clutch element 208 by means of a slot 220.

A clutch operator 222 comprises an annular ring 224 surrounding spring 218. A booth 226 is mounted on ring 224. The other end 228 of spring 218 is anchored to ring 224 by means of an opening 230. When spring 218 is in the relaxed condition, as shown, its coils are spaced slightly from clutch surfaces 211 and 216. Clutch operator 222 also comprises an arm 232 attached to a ring 234, which has a slot 236 engaging tooth 226.

Fixedly attached to second clutch element 214 is a drum 240 having a groove 242 for receiving cable 40. Extending sidewardly from drum 240 is a pin 243, which is engaged by a spring 244 wound around shaft 202 and engaging another pin 246 carried by frame 200. A pair of limit stops 250 and 252 are mounted on frame 200. A limit lever 254 having adjusting screws 256 and 258 is attached to first clutch element 208. A spring 260 biases lever 254 clockwise. A motor 264 has a shaft 266 connected to arm 232 to operate the mechanism.

In operation, spring 244 constantly biases drum 240 in the counterclockwise direction to continuously take up the slack in cable 40 caused by the increasing diameter of the yarn package. Second clutch element 214 moves freely with drum 240, but the other elements remain stationary. When the yarn package is to be lifted, motor 264 causes arm 232 to move upwardly, rotating ring 234 and operator 224 counterclockwise. Such rotation winds spring 218 more tightly about clutch surfaces 211 and 216, causing spring 218 to engage clutch surfaces 211 and 216 and thus lock clutch elements 208 and 214 together. The space between spring 218 and surfaces 211 and 216 is normally very small, so that very slight rotation of operator 224 causes engagement. During the remainder of the stroke of motor 264, the elements all rotate together, winding cable 40 upon drum 240. Stop 252 limits the stroke. When the power to motor 264 is relaxed, arm 232 rotates clockwise, as do ring 234 and operator 224, thus relaxing spring 218 and allowing it to disengage from clutch surfaces 211 and 216. Simply stated, the two clutch elements'are selectively connectable together by means of spring 218.

Modifications and variations to the structure described above are possible within the scope of the invention. For example, while the winding has been described as the movable element and the driving roll the stationary element, this could be reversed. Likewise, the operation of the invention has been described on the basis that the winding is normally being driven, and a reduction in the quantity of crimped yarn in the exit portion of the crimping chamber below a predetermined level results in a stoppage of the winding operation. However, the invention could be oriented so that the winding is normally not being driven, and driving commences when the yarn in the chamber exceeds a predetermined level. The friction surfaces, while shown smooth or knurled surfaces, could be toothed. as could the friction shoes. The motors could also be of other suitable types such as electric. It should therefore be understood that the invention is not restricted to the structure described above, but is of the scope set forth in the following claims:

We claim:

1. A winding mechanism for withdrawing yarn or the like from a treating chamber comprising:

a driving roll element driven in rotation by a driving means,

a rotatable yarn winding element upon which treated yarn is wound, at least one of said elements being movable with respect to the other of said elements,

a control means for varying the spacing between said yarn winding element and said driving roll element between the limits of full engagement and complete disengagement with one another, said control means comprising:

a rotatable drum means,

control linkage means connected on the one hand to said movable element and on the other hand to said drum means at a point spaced from the axis of rotation of said drum means so that rotation of said drum means causes movement of said linkage means,

sensing means for sensing a predetermined quantity of treated yarn to be wound on said winding element, and

means for rotating said drum means in response to said sensing means, whereby said drum means is rotated to operate said linkage means to vary the spacing between aid winding element and said driving roll element, thereby increasingor decreasing the rate of winding to maintain the quantity of yarn at said predetermined quantity.

2. A yarn winding mechanism according to claim 1 wherein said means for rotating said drum means comprises a movable friction shoe engageable with a friction surface carried by said drum means, and means for moving said friction shoe in response to said sensing means.

3. A yarn winding mechanism according to claim 2 further comprising means for limiting the movement of said friction shoe to limit the arc of rotation imparted to said drum means by said friction shoe.

4. A yarn winding mechanism according to claim 2 wherein said friction surface is on the side of said drum means and said friction shoe applies a force component tangential to said side to cause said drum means to rotate in a first direction.

5. A yarn winding mechanism according to claim 1 wherein said drum means is biased in said first direction to remove slack from said linkage means.

6. A yarn winding mechanism according to claim 5 wherein said linkage means is flexible and is attached to the periphery of said drum means, rotation of said drum means in said first direction winding said flexible linkage means onto said drum means.

7. A yarn winding mechanism according to claim 2 wherein said means for moving said friction shoe comprises:

a first arm pivotally mounted at one end and extending generally radially of said drum means, the pivot axis of said first arm being substantially parallel to the axis of rotation of said drum means,

a second arm pivotally connected at one end to the other end of said first arm and having a pivot axis substantially parallel to the axis of rotation of said drum means, said second arm having a portion adjacent to said friction surface, said friction shoe being mounted on said adjacent portion offset from the pivot axis of said second arm, whereby pivoting of said second arm with respect to said first arm initially causes said friction shoe to engage said friction surface and then causes said second arm and said first arm to pivot together about the pivot axis of said first arm with the interengaging friction shoe and friction surface causing said drum means to rotate, and

motor means connected to said second arm for pivoting said second arm.

55 8. A yarn winding mechanism according to claim 7 wherein the pivot axis of said first arm is coincident with the axis of rotation of said drum means and said first arm extends radially outwardly beyond the periphery of said drum means, and wherein said friction surface is on the outside surface of the side of said drum means and the pivot axis of said second arm is adjacent to said friction surface.

9. A yarn winding mechanism according to claim 8 wherein said friction surface comprises an inwardly generally V-shapcd groove and said friction shoe is outwardly generally V-shaped and extends into said groove.

13 10. A yarn winding mechanism according to claim 2 wherein said means for moving said friction shoe comprises: I

a first arm pivotally mounted ing generally radially of said drum means, the pivot axis of said first arm being substantially parallel to the axis of rotation of said drum means,

a second arm pivotally connected at one end to the other end of said first arm and having a cam portion offset from the pivot axis thereof, said cam portion facing said friction surface and being spaced therefrom,

said friction shoe being movably mounted interposed between said friction surface and said cam portion adjacent to said friction surface, whereby pivotal movement of said second arm initially causes said cam portion to engage said friction shoe to drive said friction shoe into engagement with said friction surface and then causes said second arm, said friction shoe, and said first arm to pivot together about the pivot axis of said first arm with the interengaging friction shoe and friction surface causing said drum means to rotate, and

motor means connected to said second arm for pivoting said second arm.

11. A yarn winding mechanism according to claim 2 wherein said means for moving said friction shoe comprises:

rod means attached to said friction shoe, said rod means positioning said friction shoe adjacent to said friction surface and being movable axially and pivotally to engage said friction shoe with said friction surface and to impart rotation to said drum means, whereby axial movement of said rod means initially engages said friction shoe with said friction surface and continued axial and pivotal movement of said rod means applies a force component to said drum means tangential to said friction surface, and

means for moving said rod means in response to said sensing means.

12. A yarn winding mechanism according to claim 11 wherein said means for moving said rod means comprises a pivotally mounted expansible chamber motor and said rod means comprises a piston rod operated by said expensible chamber motor.

13. A yarn winding mechanism according to claim 12 wherein said friction surface is located on the inside surface of the side of said drum means, and said expansible chamber motor, said piston rod and said friction shoe are mounted within said drum means.

14. A yarn winding mechanism according to claim 13 wherein said motor is pivotally mounted at the end opposite said piston rod, and further comprising an adjustable stop engaging said motor and limiting the pivotal movement thereof in one direction to establish the normal position of said motor with said friction shoe spaced from said friction surface, thereby limiting the arc of rotation applied to said drum means.

15. A yarn winding mechanism according to claim 13 wherein said friction shoe comprises a peripheral surface of a disc rotatably mounted on one end of a disc mounting lever, said piston rod being connected to said disc at a point spaced from the axis of rotation of said disc, said disc mounting lever being mounted at the other end for pivotal and axial movement, and including means for limiting the arc of rotation applied to said at one end and extenddrum means by said friction shoe comprising an adjust-' able disc stop on saiddisce'ngageable with said disc 4 mounting lever to limit the rotation of said disc, whereby axial movement of said piston rod initially rotates said dise until said disc stop engages said disc mounting lever, and continued axial movement of said piston rod moves said disc into engagement with said surface and then applies a force tangential to said friction surface to cause said drum means to rotate, said disc mounting lever then moving axially.

16. A yarn winding mechanism according to claim 15 wherein said disc mounting lever is mounted on a pin and slot connection positioned adjacent to the inner surface of said drum means, said slot being generally aligned with the inner surface of said drum means, said disc mounting lever being biased to hold said disc normally out of engagement with said friction surface.

17. A yarn winding mechanism according to claim 1 further comprising yarn break sensing means positioned along the path of said yarn between said treating chamber and said yarn winding element, and

means actuated by said yarn sensing means connected to said movable element to disengage said yarn winding element and said driving roll element upon sensing a break in the yarn, said means actuated by said yarn sensing means comprising:

an axially movable beam connected to said movable element, said beam having a toothed portion,

a beam operating arm for moving said beam axially, and,

a pawl loosely attached to said beam operating arm and engaging said toothed portion to allow a predetermined amount of axial movement of said beam uninhibited by said beam operating arm, whereby movement of said beam operating arm moves said beam by means of said pawl.

18. The apparatus according to claim 1 wherein said means for rotating said drum comprises a driven clutch element attached to said drum, a driving clutch element operatively connected to clutch rotation means, and clutch engagement means for selectively connecting together said driven clutch element.

19. The apparatus according to claim 18 wherein said driven clutch element comprises a rotatably mounted cylindrical driven clutch surface and said driving clutch element comprises a rotatably mounted cylindrical driving clutch surface disposed adjacent to and coaxial with said driven clutch surface, and wherein said clutch engagement means comprises wire spring means coiled about said clutch surfaces and generally coaxial therewith, said spring means being movable between a disengaged position spaced slightly from at least one of said clutch surfaces and an engaged position contacting both of said clutch surfaces to thereby lock said clutch elements together, and further comprising means for moving said spring means between said positions.

20. The apparatus according to claim 19 further comprising a rotatable clutch operator generally coaxial with said driving clutch element, one end of said spring means being attached to said driving clutch element and the other end of said spring means being attached to said clutch operator whereby rotation of said clutch operator in one direction causes said spring means to move said engaged position and rotation of 22. The apparatus according to claim 18 further comprising stop means for limiting the amount of rota- 'tion of said drum during activation of said means for moving said spring.

23. The apparatus according to claim 18 further comprising spring means biasing said drum in one direction to take up slack in said cable.

l =l l 

1. A winding mechanism for withdrawing yarn or the like from a treating chamber comprising: a driving roll element driven in rotation by a driving means, a rotatable yarn winding element upon which treated yarn is wound, at least one of said elements being movable with respect to the other of said elements, a control means for varying the spacing between said yarn winding element and said driving roll element between the limits of full engagement and complete disengagement with one another, said control means comprising: a rotatable drum means, control linkage means connected on the one hand to said movable element and on the other hand to said drum means at a point spaced from the axis of rotation of said drum means so that rotation of said drum means causes movement of said linkage means, sensing means for sensing a predetermined quantity of treated yarn to be wound on said winding element, and means for rotating said drum means in response to said sensing means, whereby said drum means is rotated to operate said linkage means to vary the spacing between aid winding element and said driving roll element, thereby increasing or decreasing the rate of winding to maintain the quantity of yarn at said predetermined quantity.
 2. A yarn winding mechanism according to claim 1 wherein said means for rotating said drum means comprises a movable friction shoe engageable with a friction surface carried by said drum means, and means for moving said friction shoe in response to said sensing means.
 3. A yarn winding mechanism according to claim 2 further comprising means for limiting the movement of said friction shoe to limit the arc of rotation imparted to said drum means by said friction shoe.
 4. A yarn winding mechanism according to claim 2 wherein said friction surface is on the side of said drum means and said friction shoe applies a force component tangential to said side to cause said drum means to rotate in a first direction.
 5. A yarn winding mechanism according to claim 1 wherein said drum means is biased in said first direction to remove slack from said linkage means.
 6. A yarn winding mechanism according to claim 5 wherein said linkage means is flexible and is attached to the periphery of said drum means, rotation of said drum means in said first direction winding said flexible linkage means onto said drum means.
 7. A yarn winding mechanism according to claim 2 wherein said means for moving said friction shoe comprises: a first arm pivotally mounted at one end and extending generally radially of said drum means, the pivot axis of said first arm being substantially parallel to the axis of rotation of said drum means, a second arm pivotally connected at one end to the other end of said first arm and having a pivot axis substantially parallel to the axis of rotation of said drum means, said second arm having a portion adjacent to said friction surface, said friction shoe being mounted on said adjacent portion offset from the pivot axis of said second arm, whereby pivoting of said second arm with respect to said first arm initially causes said friction shoe to engage said friction surface and then causes said second arm and said first arm to pivot together about the pivot axis of said first arm with the interengaging friction shoe and friction surface causing said drum means to rotate, and motor means connected to said second arm for pivoting said second arm.
 8. A yarn winding mechanism according to claim 7 wherein the pivot axis of said first arm is coincident with the axis of rotation of said drum means and said first arm extends radially outwardly beyond the periphery of said drum means, and wherein said friction surface is on the outside surface of the side of said drum means and the pivot axis of said second arm is adjacent to said friction surface.
 9. A yarn winding mechanism according to claim 8 wherein said friction surface comprises an inwardly generally V-shaped groove and said friction shoe is outwardly generally V-shaped and extends into said groove.
 10. A yarn winding mechanism according to claim 2 wherein said means for moving said friction shoe comprises: a first arm pivotally mounted at one end and extending generally radially of said drum means, the pivot axis of said first arm being substantially parallel to the axis of rotation of said drum means, a second arm pivotally connected at one end to the other end of said first arm and having a cam portion offset from the pivot axis thereof, said cam portion facing said friction surface and being spaced therefrom, said friction shoe being movably mounted interposed between said friction surface and said cam portion adjacent to said friction surface, whereby pivotal movement of said second arm initially causes said cam portion to engage said friction shoe to drive said friction shoe into engagement with said friction surface and then causes said second arm, said friction shoe, and said first arm to pivot together about the pivot axis of said first arm with the interengaging friction shoe and friction surface causing said drum means to rotate, and motor means connected to said second arm for pivoting said second arm.
 11. A yarn winding mechanism according to claim 2 wherein said means for moving said friction shoe comprises: rod means attached to said friction shoe, said rod means positioning said friction shoe adjacent to said friction surface and being movable axially and pivotally to engage said friction shoe with said friction surface and to impart rotation to said drum means, whereby axial movement of said rod means initially engages said friction shoe with said friction surface and continued axial and pivotal movement of said rod means applies a force component to said drum means tangential to said friction surface, and means for moving said rod means in response to said sensing means.
 12. A yarn winding mechanism according to claim 11 wherein said means for moving said rod means comprises a pivotally mounted expansible chamber motor and said rod means comprises a piston rod operated by said expensible chamber motor.
 13. A yarn winding mechanism according to claim 12 wherein said friction surface is located on the inside surface of the side of said drum means, and said expansible chamber motor, said piston rod and said friction shoe are mounted within said drum means.
 14. A yarn winding mechanism according to claim 13 wherein said motor is pivotally mounted at the end opposite said piston rod, and further comprising an adjustable stop engaging said motor and limiting the pivotal movement thereof in one direction to establish the normal position of said motor with said friction shoe spaced from said friction surface, thereby limiting the arc of rotation applied to said drum means.
 15. A yarn winding mechanism according to claim 13 wherein said friction shoe comprises a peripheral surface of a disc rotatably mounted on one end of a disc mounting lever, said piston rod being connected to said disc at a point spaced from the axis of rotation of said disc, said disc mounting lever being mounted at the other end for pivotal and axial movement, and including means for limiting the arc of rotation applied to said drum means by said friction shoe comprising an adjustable disc stop on said disc engageable with said disc mounting lever to limit the rotation of said disc, whereby axial movement of said piston rod initially rotates said disc until said disc stop engages said disc mounting lever, and continued axial movement of said piston rod moves said disc into engagement with said surface and then applies a force tangential to said friction surface to cause said drum means to rotate, said disc mounting lever then moving axially.
 16. A yarn winding mechanism according to claim 15 wherein said disc mounting lever is mounted on a pin and slot connection positioned adjacent to the inner surface of said drum means, said slot being generally aligned with the inner surface of said drum means, said disc mounting lever being biased to hold said disc normally out of engagement with said friction surface.
 17. A yarn winding mechanism according to claim 1 further comprising yarn break sensing means positioned along the path of said yarn between said treating chamber and said yarn winding element, and means actuated by said yarn sensing means connected to said movable element to disengage said yarn winding element and said driving roll element upon sensing a break in the yarn, said means actuated by said yarn sensing means comprising: an axially movable beam connected to said movable element, said beam having a toothed portion, a beam operating arm for moving said beam axially, and, a pawl loosely attached to said beam operating arm and engaging said toothed portion to allow a predetermined amount of axial movement of said beam uninhibited by said beam operating arm, whereby movement of said beam operating arm moves said beam by means of said pawl.
 18. The apparatus according to claim 1 wherein said means for rotating said drum comprises a driven clutch element attached to said drum, a driving clutch element operatively connected to clutch rotation means, and clutch engagement means for selectively connecting together said driven clutch element.
 19. The apparatus according to claim 18 wherein said driven clutch element comprises a rotatably mounted cylindrical driven clutch surface and said driving clutch element comprises a rotatably mounted cylindrical driving clutch surface disposed adjacent to and coaXial with said driven clutch surface, and wherein said clutch engagement means comprises wire spring means coiled about said clutch surfaces and generally coaxial therewith, said spring means being movable between a disengaged position spaced slightly from at least one of said clutch surfaces and an engaged position contacting both of said clutch surfaces to thereby lock said clutch elements together, and further comprising means for moving said spring means between said positions.
 20. The apparatus according to claim 19 further comprising a rotatable clutch operator generally coaxial with said driving clutch element, one end of said spring means being attached to said driving clutch element and the other end of said spring means being attached to said clutch operator whereby rotation of said clutch operator in one direction causes said spring means to move said engaged position and rotation of said clutch operator in the other direction causes said spring means to move to said disengaged position.
 21. The apparatus according to claim 20 wherein said clutch operator is rotatable in said one direction beyond the point at which said spring means reaches said engaged position, such continued rotation causing said clutch elements to be rotated together to wind said cable upon said drum.
 22. The apparatus according to claim 18 further comprising stop means for limiting the amount of rotation of said drum during activation of said means for moving said spring.
 23. The apparatus according to claim 18 further comprising spring means biasing said drum in one direction to take up slack in said cable. 